Thermal Characteristics of an Electric Furnace under Micro-Gravity

The paper describes the structure and specifications of the compact electric furnace used to perform materials-processing experiments on the TT-500 A rocket as part of the Japanese microgravity utilization program. Experimental results on the operation of the furnace under microgravity conditions are compared with results obtained from ground experiments, and the effect of helium convection on the temperature distribution in the furnace is assessed. It is shown that the temperature of the sample (carbon whisker coated with aluminum alloy) under microgravity was slightly higher than that in the ground experiment, which temperature difference is probably due to the convection of helium under gravity. The temperature difference between the two experiments was considered to be so small that the temperature history in the microgravity experiment could easily be controlled with a feedback controller using results of the preliminary ground experiment.